The implications of those cases depend on the interpretation of the National Environmental Policy Act (NEPA), Barron told the publication. If NEPA is read as strictly procedural, the climate assessment needs to be complete, but the agency does not necessarily have to choose the alternative with the least impact, he said. If identifying greenhouse gas emissions instead requires the agency to avoid said emissions, he said, the rulings pack a more substantial punch.

“Either way, it will add time and cost to environmental review,” Barron said. “That's the minimum impact it would have.”

If recent court decisions persuade BLM to cancel lease sales or withhold parcels for which environmental review is complete, he added, industry interests could revive a now-dormant lawsuit that prodded the Obama administration to hold quarterly lease sales.

"If there are any parcels for which environmental review is complete, then BLM has a nondiscretionary duty to offer those parcels," Barron told E&E News.